Upper limit for the D2H+ ortho-to-para ratio in the prestellar core 16293E (CHESS) C. Vastel, P. Caselli, C. Ceccarelli, A. Bacmann, D. C. Lis, E. Caux, C. Codella, J. A. Beckwith and T. Ridley A&A, 547 (2012) A33 Published online: 24 October 2012 DOI: 10.1051/0004-6361/201219616